Electrical apparatus



Jan. 15, 1935.

A. GLASER ELECTRICAL APPARATUS Filed July 9, 1931 Inventor: AugustGlaser,

H is Att orn ey- Patented Jan. 15, 1935 'ration o f New York IApplication Jur g'ag 193 1, Se

signor to GeneralElectricjCompany,za 'corpo- My invention relates toelectrical apparatus for generating. intermittentcurrents; and moreparticularly to such apparatus including angel fric valve for:generating 10w frequency, inter i hittent, unidirectional currents;-

fle retofore there havefbeen p s'ed various arrangements utilizing gridcon led electric Valves for generating alternating currentorintermittent unidirectional current; With certain arrangements of theprior art,' however; it has been found either: impossible to f generateperiodic currentshaving ajlowjrequency or 1111*- pr'acticalto generatethese low frequency-cur rents because of the variability 'of the ciicuitelements upon Whichthe frequency of the system depends. v

It is an object of myjnv ention to provide an improved; electric circuitincluding a gridf'controlled electricvamew ngu-{wn'1 generate anintermittent current of very low frequency, f of example, a frequency ofseveral cycles per It is a further object ofmyinventiorito" pro vide animproved; electric circuit includingagrid controlled -"electric' talvewhich will generate aperiodic current of substantially constant frequency irrespective of variationsin surrounding fi v l t Whilemy"in'ventionisof general application, it is particularly adapted foruse in inte'rmittentlyturning off and on electric lamps, such forexampleas ar'e'usedin beacon lights-, danger signals, namesi nals; etc,InLaccOrdanceWith my l invention, a loadeircuit is connected tov asource; of current or "energy supply c'ir'cujits through an electricva1ve'. A condenser, a photoelectric cell and a' lightjisoure,energizedfrom the. load circuit, coopefatetonrender the electric Valvealternately conductive on-emcee; ti ve. In this manner-the loadrcircuit'is inter mittently energized at a frequency depenc ling u-pomtheconstants of theapparatus for example the thermal characteristics ofthe; light source, the size of the condenser, etc'. Accorde ing'. to onemodification of my invention; the

photo-electric cell is also exposed to'the ambient illumination by meansO'f 'whichth'e' apparatus is maintained inoperative for a} predeterminedintensity of illumination, forexample normal daylight, and isautomatically setinto opera tion when the ambient illumination dropsfbelow t (c i- 2 F controlled many desired manner no control tireop'e'rati'on of the-apparatus; 1"?) t i or a better understaf or; mymention together with other' and further jobj'cts' thereof;

reference isf'lriad to the I mn wifig description; taken in "'cormecti'on with the acc mpan ing" pointed." out iii n i t g l o rReferring: now' to the'j drawing I iiavevinfi:

trated "an" arrangement for transferring energy from anelectricalenergy'supply" circuitbr a source or alternatingcurrent' 10 to 2;load-circuit 1 represented by the device 11. This apparatusincluds'transformer' lz' I having a rimary Winding I connected to thealternating; current supply circuit lOjand; a secondary win ngro; vided;with: an electrical midpo nt; The 'ldad i6 circuit representedby' thedevice" -1'1,is'- conneeteo I across one half of the; secondary windingtbug-rt an' electricfvalve '13. E1et iva1ve 13 is'prd ridged-with ananode, a oathode', and a confirm grid and may be of f a'ny of ;thei'seveifal-tyfieswell known in the "art, aIthjoughQiI prefrl o use avalve of the vapor electric d'is nargetype- Theoath e; of the valve "13'is" preferably to the midpoint of the transformer- Winding!- Connected;across the fullfsecondary wmam the transformer -is a series circuit includ'i variable condenser I4,j a"'1ig' responsive Iii such as aphoto-electric cell 15," and; if ces a protective'resistor 16; m'somecases be desirable to 2011mm a); h gh discharge resist" ance I7across"the" cdriderrser l4, -esfiee1 a in case the resistance; ofthe-photo electric c'elF I5; wheneda'rk, is extremely high: The prime:electriccll 1 5' i'sadapted -to be illi'iiiiified-f a; lamp 18= which isconnected across the d circuit repres nted 'byth ydvice Ili thfoiigfi-af variable resistor 1'9.- As-indicated Kittie dotted line, thephoto-electric cel1 f-15 'ai1d: tli'e"1amp* 18" preferaloly' comprise a?smgleendlosea ilhifvy maybe omitted or so constructed that the'photoelectric 1l 1 5 is ex osed to these" ol'fiidih'g illumination so that'the apparatusis m an imperative conditi'bfi"wheneief the" ill-'11minatiorr is above a; predtrmmed iiitehsitiL-sai Iribthr cases it may bedesirable topro'vid an additional light source 20" Whih may be 'energi'zed (from a battery 21' through amanually-1 operable: switchZZQ-lOcated eithe'r in a local 'orr Y a-r'mote station. By -this meansiti-i'spossiblei to control the operation of the apparatus by the switch22. In case the electric valve 13 is one which itself generates aconsiderable amount of light the lamp 18 may be omitted and electricvalve 13 maybe substituted therefor in cooperative relation with thephoto-electric cell 15.

In explaining, the operation ofthe above described -apparatus it will beassumed that,.-initially, electric valve 13 is conductive and that theload circuit represented by the device 11 and lamp 18 are energized.Under these conditions the resistance of the photo-electric" cell 15"isgreatly reduced and, during the half cycle of. the alternating supplypotentialwhen the electric valve 13 is conducting current, that is, whenthe left hand terminal of the secondary of transformer 12 is positivewith respecttoits right hand terminal, the condenser 14 becomes.

charged to substantially the full potential of the secondary winding ofthe transformer, the right hand terminal of the condenser approachingthat of 'the right handjte'rminal of the transfdrxiier'Winding. Atthesarne time the grid po-. tential of electric valve 13 approaches thatof the right hand terminal of the secondary winding of the; transformer12' and hence becomes negative with" respect {to' its" cathode potentialduring those half cycles when the valve 13 [would normally beconductive. Thevalve 13ijs 'now rendered completely non-conductive, thecurrent to .the load circuitll is interrupted andthelamp 18 is'deenergized. As'the lamp 18 cools off and its illumination decreases,the resistance of the photo-electric cell 15 increases to substantiallyaninfinite value and the charge on the condenser 14 leaks ofi throughits charging circuit or, if the resistance ofv the photo-electric cellis to'o high, through the discharge resistoifl'l. When the condenser 14is substantially completely discharged, it-will be noted that the gridpotential. of the vvalve 13 approaches the potential of the left handterminal of the transformer winding, which, of course, is positive withrespect tothe 'cathodepotential ot'pvalve 13 during the 5 f c s fwha theva vai m mal f id i tive. Inthis way the valve 13 is again renderedconductive, current is supplied to the load circuit represented by thedevice lljand the lamp 18 again energized. 'I'h e abovede'scribed cycleis repeated indefinitely and intermittent current impulsesare suppliedto the load circuitrepresented by the device 11. It will beapparent thatthe frequency of the intermittent current impule's are dependentprimarily upon the value of the condenser 14 and the thermalcharacteristics; of thelampf 18, so that this frequency may be variedwithin wide limits by properly selectingv the constants of those twoelements, or, as illustrated,;the condenser 14 maybe made vari able anda variable resistor 19 may be included in the circuit of the lamp 18 sothat frequency may be changed at will.

As stated above, if the enclosing casing surrounding thephoto-electriccell 15 and the lamp' 18 isomitted orif this casing is so constructedthat, they photo-electric cell 15 is exposed to the surroundingillumination, the apparatus will be maintained in an inoperativecondition wheneverthe surrounding illumination exceeds apredeterminedintensity. By: this means the apparatus may beused toautomatically turn on a flashing circuit or:any intermittently energizedload circuitiwhenever the daylight illumination falls,belowapredetermined intensity. It will be obvi-,

ous also that a similar manual control is obtained by means of theauxiliary lamp 20, the

battery 21 and the switch 22. It will also be obvious to those skilledin the art that, if the valve 13generates a suflicient illumination forcontrolling the photo-electric cell 15, the lamp 18 may be replaced bythe valve 13in the circuit illustrated. v 5

While I have described'what'l at present consider the preferredembodiment of my invention, it will be obviousto those skilled in theart that various changes and modifications may be made without departingfrom my invention and I therefore aim in the appended claims 'toacoverall such changes and modifications as fall within the true spirit andscope of my v t onrzi "WhatI claim as new and desire to secure byLetters Patent of the United States, is:

' 1; "Apparatus for generating intermittent current impulses comprisinga sourceof current,*a,

load circuit, an electric valve comprising an anode, ajcathode," and acontrol element, and

interconnecting said sourceand said load 'cir cuit, andmeans including alight responsive means, a,tirne responsive device and'a source of lightenergized from said a load circuit for periodically renderingsaidyalvealternately conductive and non-conductive. r 2. Apparatus forgenerating intermittent cur: rent impulses comprising a source ofcurrent, a load circuit, meansinterconnecting;said source and said loadcircuit including anelectric valve provided with a control, grid, acircuit including a condenser and a pheto-electric cell connected tosaid source for normally impressingapositive potential upon said grid,and, a light source ;en-'

ergizedjfrom said load circuit for illumining said cell to charge saidcondenser thereby to reduce the positive potentialupo'n said; grid.

3. Apparatus for generating intermittent cur;

rent impulses comprising a source of alternating current, a transformerwinding; connected thereto and provided with an electrical midpoint, a

load circuit, and means forconnecting said' load circuit across oneportion of said winding including an, electric valve provided with ananode, a'cathode' and a control grid,- a errant,

including a condenser and a photo-electricjcell' serially connectedacross, said transforineriwinding, the grid of said valve being'connected to the common connection of. said condenserjand photo'el'ectric cell, and a light source energized an electric valveinterconnecting saidsource and;

said load circuit, and comprising an anode, a; cathode, and a controlelement, a circuit 'includ-.

ing a photo-electric cell for rendering said valve conductive when saidcell is unillumined, said cell being-normally exposed to an ambientillumination to maintain said valve non-conductive] and independentmeans for illumining "said 1 cell;

are deliveredto said load circuit only when the ambient illuminationdrops below a predetermined intensity.

6. Apparatus for generating intermittent current impulses comprising asource of current; a load circuit, a discontinuous control electricvalve comprising an anode, a cathode and a control element, said valvebeing connected between said source and said load circuit, .a circuitincluding a photo-electric cell and a condenser interconnecting saidsource of current and said control element for controlling theconductivity of said valve, and means for illumining said cell inaccordance with the conductivity of said valve.

AUGUST GLASER.

